Yes I've also been having this problem but not the same error message. I get the "activation could not be processed at this time. Please try again later" message.
After reading around I learned that this might be because I was using an old and inactive SIM in my 4S but even after swapping my sister's active SIM and my SIM from my iPhone 5, nothing seems to work. I'm constantly stuck at activation even after DFU restores to iOS7.1.2 and 8.0 GM.
Has anyone found solutions to these problems?